1. Field of the Invention
The present invention relates to a substrate processing apparatus and substrate processing method for coating a glass substrate (LCD substrate) for a semiconductor wafer and liquid crystal display with resist, and for developing the exposed resultant.
2. Description of the Related Art
Jpn. Pat. Appln. KOKAI Publication No. 2002-217264 discloses a system in which a coating/developing apparatus for executing a photolithography process of a semiconductor device is combined with an exposure device. FIG. 14 shows an outline of a conventional system. A coating/developing apparatus 1 is provided with a carrier placing section 1A, a treatment block 1B and an interface section 1C. An exposure device 1D is connected to the coating/developing apparatus 1 through the interface section 1C. A delivery arm 11 for transferring a wafer W to the treatment block 1B is provided in the carrier placing section 1A. Main carrier arms 12-1 and 12-2 are provided in the treatment block 1B. The main carrier arms 12-1 and 12-2 are each provided with, for example, three arm holders which are movable forward, backward and vertically, and horizontally rotatable. Heating units, shelf units 13 and chemical treatment units 14 are arranged around the main carrier arms 12-1 and 12-2. The chemical treatment unit 14 includes a coating unit for a reflection preventing film, a resist coating unit, and a developing unit. The shelf unit 13 includes a stack of cooling units as high-precision temperature control sections.
The shelf unit 13 includes delivery units (not shown) for delivering substrates; one delivery unit delivering a substrate between the delivery arm 11 and the main transfer arm 12-1, another delivery unit delivering a substrate between the delivery arm 11 and the main transfer arm 12-1, and an additional delivery unit delivering a substrate between the main transfer arm 12-2 and a transfer arm (not shown) in the interface section 1C.
A path where the wafer W is carried out from a carrier C and to the exposure device 1D is referred to as a “going path”, and its reverse path is referred to as a “return path”. When traveling through the going path, the wafer W is subjected to various processings for forming a resist film, and when traveling through the return path, the wafer is subjected to a processing for developing a resist film after it is exposed. A transfer path of the wafer W to execute the photolithography process is: carrier C→coating unit for a reflection preventing film (chemical treatment unit 14)→cooling unit (shelf unit 14)→resist coating unit (chemical treatment unit 14)→heating unit→cooling unit→interface block 1C→exposure device 1D→interface block 1C→heating unit→cooling unit→developing unit (chemical treatment unit 14)→cooling unit→carrier C.
To transfer the wafer W, a transfer recipe describing a transfer order of the wafer W is input to a computer. In turn, the computer creates a transfer schedule according to the transfer recipe.
The unit and the stage where the wafer W is to be placed will be referred to as a “module”. The “transfer recipe” is a table describing the transfer order of the wafer W assigned to modules. A “transfer schedule” is a timetable in which transfer cycles (phases) are time sequentially arranged as shown in FIG. 8, for example. “Phase” defines the wafer W and the modules where the wafer W is to be located in order to transfer the wafer W between the modules along and over a range from the upstream to the downstream of a transfer path including the going path and the return path.
Accordingly, the computer refers to this phase to drive the delivery arm 11, the main carrier arms 12-1 and 12-2, and the transfer arm (not shown) in the interface block 1C so as to satisfy the positional relationship between the wafer W and the modules as described in the phase, and executes one phase, followed by execution of a next phase. In this way, the computer sequentially executes the phases, so that the wafer W sequentially moves along the known transfer path.
In such a system, the number of modules is large, and the processing times for the modules are different from one another. In this respect, how to gain high throughput of the system is of very important significance. To spread the loads of transfer, the modules are shared by the two main carrier arms 12-1 and 12-2 in the treatment block 1B.
Meanwhile, one phase contains the transfer operation by the first main carrier arm 12-1 and that by the second main carrier arm 12-2. When the first main carrier arms 12-1 or 12-2 complete the transferring job of transferring the wafer W to modules allotted to itself in a phase, they return to their original positions, and stand by until a next phase starts.
Recently, the throughput of the exposure device 1D tends to increase. With this, there is a demand of increasing the throughout also in the coating/developing apparatus 1. However, the throughput of the conventional coating/developing apparatus 1 is not so high. For this reason, the coating/developing apparatus 1 hinders the improvement of the throughput of the overall system.